CAPACITY FOR HEAT OF METALS AT LOW TEMPERATURES. 
331 
For 0 + fy = 0 O the radiation term vanishes, hence, if d6 N /dt denotes the value of the 
ordinate at this point, 
n- E 2 
dt JR/(MS+ms)’ 
( 4 ) 
which enables the value of the specific heat to be deduced. 
As an illustration of the method, one experiment in the case of zinc at —64° Pt may 
be quoted. 
All temperatures are expressed on the platinum scale, the conversion being effected 
by the factor ■ r (= f) in the final reduction. 
d{pt) 
Table V. 
I. Warming up under Radiation. 
Temperature. 
a« 
a * 10 - 
Temperature. 
d9 
^ x 104 
dt 
-66-75 
3-87 
-66-63 
3-81 
-66-71 
3-84 
-66-59 
3-77 
-66-67 
3-99 
II. Electrical Supply on. 
Temperature. 
(e+di). 
d0 
a* 101 - 
Temperature. 
( 9 +Op 
a e 
a °- 
-65-44 
35-78 
-63-03 
33-09 
-65-04 
35-44 
-62-63 
32-51 
-64-64 
34-98 
-62-23 
32-13 
-64-23 
34-31 
-61-87 
31-59 
-63-83 
34-01 
-61-47 
31-15 
-63-43 
33-57 
III. Cooling down by Radiation. 
Temperature. 
8 o 
5-x 104 
dt 
Temperature. 
3D 
5 x 0 • 
-61-35 
2-65 
-61-47 
2-54 
-61-39 
2-66 
-61-51 
2-53 
-61-43 
2-60 
The data for computing III. in the above table were obtained from the following 
observations of temperature and time, after switching off the electrical supply :— 
2 u 2 
